M1 Support Forum M1XSP in Serial Expander Mode does not correctly transmit ^ character Reply To: M1XSP in Serial Expander Mode does not correctly transmit ^ character

#5400
Jeffrey Bakken

    The “Help” button on the ELK RP2 “Text String” edit dialog states “Because the caret symbol (^) is used to define the special characters, to insert it literally into a string, you must enter ^@.”

    I intend to send the literal string “A^A002” from the M1XSP RS232 port, so I set the text string to “A^@A002”  I expect the RS232 character sequence sent from the M1XSP to be: (hex) 41, 5E, 41, 30, 30, 32.  Instead, the actual sequence sent from the M1XSP is: (hex) 41, 01, 30, 30, 32.  It appears that the ‘@’ character is ignored and the ‘^’ operator is applied to the following ‘A’, treating it as a special (control) character.  Stated differently, the three-character text string “^@A”, is treated by the M1XSP the same as if it were the two-character string “^A” – substituting in its place a single special character – rather than achieving the expected result of sending the literal pair of characters ‘^’ and ‘A’.

    Is ‘@’ the correct trailing-escape character to send a literal ‘^’?  Have I missed something in the M1XSP setup?  If this is a known issue, is there a work-around for it?

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